Digestive System Functions
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Questions and Answers

What is the primary function of the mouth in the digestive system?

Mastication of food

Which organ serves as a passageway for air and food?

  • Pharynx (correct)
  • Stomach
  • Mouth
  • Esophagus
  • The stomach is the primary site of nutrient absorption into the blood.

    False (B)

    Food is propelled to the esophagus by two _____ layers.

    <p>muscle</p> Signup and view all the answers

    What are the structural and functional units of the kidneys?

    <p>Nephrons</p> Signup and view all the answers

    What composes the renal corpuscle in a nephron?

    <p>Bowman's Capsule (A), Glomerulus (B)</p> Signup and view all the answers

    The collecting ducts are part of the nephron.

    <p>False (B)</p> Signup and view all the answers

    Which specialized capillary bed filters fluid from the blood into the renal tubule?

    <p>Glomerular capillaries</p> Signup and view all the answers

    What is the primary role of the villi in the small intestine?

    <p>Increase surface area for absorption</p> Signup and view all the answers

    Which organ is responsible for the majority of fat digestion?

    <p>Pancreas (D)</p> Signup and view all the answers

    The __________ absorbs water along the length of the small intestine.

    <p>intestine</p> Signup and view all the answers

    The large intestine does not participate in the digestion of food.

    <p>True (A)</p> Signup and view all the answers

    Match the following structures with their correct functions:

    <p>Colon = Descending - travels down the left side Ileocecal valve = Between small &amp; large intestine Rectum = Holding area before release of fecal material Appendix = Accumulation of lymphatic tissue; can become inflamed</p> Signup and view all the answers

    What is the function of fructose in semen?

    <p>It provides energy for sperm cells.</p> Signup and view all the answers

    Where does sperm enter from?

    <p>Ejaculatory duct (A)</p> Signup and view all the answers

    Spermatic cord consists of ductus deferens, blood vessels, and nerves in a connective tissue sheath. It ends in the ______ duct.

    <p>ejaculatory</p> Signup and view all the answers

    The urethra carries both urine and sperm.

    <p>True (A)</p> Signup and view all the answers

    Match the regions of the penis with their descriptions:

    <p>Root = Most proximal, fixed part of the penis Body = Free part suspended between the root and glans Glans = Most distal part of the penis</p> Signup and view all the answers

    Where does fertilization occur?

    <p>Fallopian Tubes (B)</p> Signup and view all the answers

    Oogonia are present at birth.

    <p>False (B)</p> Signup and view all the answers

    What hormone helps maintain pregnancy?

    <p>Progesterone</p> Signup and view all the answers

    ______ are finger-like projections at the distal end that receive the oocyte.

    <p>Fimbriae</p> Signup and view all the answers

    Match the following hormones with their descriptions:

    <p>Estrogens = Cause secondary sex characteristics Progesterone = Helps maintain pregnancy hCG = Secretes human chorionic gonadotropin</p> Signup and view all the answers

    What is the main function of aldosterone in the regulation of water balance?

    <p>prevent excessive water loss in urine</p> Signup and view all the answers

    Urine commonly has a pH range of ___ to ___.

    <p>4.5 to 8.0</p> Signup and view all the answers

    What is the main function of the urethra?

    <p>Carry urine from the bladder to the outside of the body (B)</p> Signup and view all the answers

    Alkalosis occurs when the blood pH falls below 7.35.

    <p>False (B)</p> Signup and view all the answers

    What is the function of the epididymis in the male reproductive system?

    <p>mature and store sperm cells</p> Signup and view all the answers

    What is the primary function of the gall bladder?

    <p>Stores bile from the liver</p> Signup and view all the answers

    Which of the following are categories of nutrients? (Select all that apply)

    <p>Lipids (A), Carbohydrates (B), Minerals (C), Proteins (D), Vitamins (E)</p> Signup and view all the answers

    Jaundice occurs when bile enters the bloodstream and tissues become yellow.

    <p>True (A)</p> Signup and view all the answers

    Carbohydrates are broken down to form ______.

    <p>ATP</p> Signup and view all the answers

    Match the following regions of the kidney with their descriptions:

    <p>Renal cortex = outer region, forms an outer shell Renal medulla = inside the cortex, contains medullary pyramids Renal pelvis = inner collecting tube, divides into major and minor calyces</p> Signup and view all the answers

    What are the two phases of breathing that make up the process of respiration?

    <p>Inspiration and expiration (A)</p> Signup and view all the answers

    What is the function of the human respiratory system?

    <p>Exchange blood carbon dioxide (CO2) with air oxygen (O2), absorb oxygen to produce energy, and discharge carbon dioxide.</p> Signup and view all the answers

    Breathing consists of two phases, inspiration and __________.

    <p>expiration</p> Signup and view all the answers

    Match the components of the respiratory system with their description:

    <p>Larynx = Maintains open airway and routes food and air appropriately Trachea = Transports air to and from lungs Lungs = Transport air to alveoli for gas exchange</p> Signup and view all the answers

    Gas exchange between blood and alveoli is an active process.

    <p>False (B)</p> Signup and view all the answers

    What is the formula for calculating Cardiac Output (CO)?

    <p>CO = HR x SV</p> Signup and view all the answers

    What is the function of the Sinoatrial node in the heart?

    <p>Acts as a pacemaker setting the heart's pace (C)</p> Signup and view all the answers

    Decreased heart rate can be caused by the Parasympathetic nervous system.

    <p>True (A)</p> Signup and view all the answers

    ___ circulation routes blood through a long loop to all parts of the body and returns to the heart.

    <p>Systemic</p> Signup and view all the answers

    Match the following components of the heart with their functions:

    <p>Coronary arteries = Supply oxygen-rich blood to the heart muscle Cardiac veins = Drain blood from the heart muscle Atrioventricular node = Located at the junction of the right and left atria and ventricles Purkinje fibers = Specialized fibers that conduct electrical impulses in the heart</p> Signup and view all the answers

    Study Notes

    Overview of Digestion

    • Digestive system: breakdown of ingested food, absorption of nutrients, and passage of waste products
    • Two main groups of organs: alimentary canal (nutrition) and accessory digestive organs

    Mouth (Oral Cavity) Anatomy

    • Vestibule: space between lips externally and teeth and gums internally
    • Tongue: attached at hyoid and styloid processes, and by the lingual frenulum
    • Frenulum: membrane that secures the tongue to the floor of the mouth, limits movement
    • Tonsils: palatine tonsils and lingual tonsil

    Pharynx

    • Serves as a passageway for air and food
    • Food is propelled to the esophagus by two muscle layers (peristalsis)

    Esophagus

    • Runs from pharynx to stomach through the diaphragm
    • Conducts food by peristalsis (slow rhythmic squeezing)
    • Passageway for food only (respiratory system branches off after the pharynx)

    Stomach

    • Acts as a storage tank for food
    • Site of food breakdown
    • Chemical breakdown of protein begins
    • Delivers chyme (processed food) to the small intestine
    • Produces 2-3L/day of gastric juice (HCl, enzymes, and mucus)
    • Regulated by neural and hormonal factors

    Small Intestine

    • Site of nutrient absorption into the blood
    • Muscular tube extending from the pyloric sphincter to the ileocecal valve
    • Approximately 4-8 hours for food to pass through
    • Subdivisions: duodenum (5%), jejunum (40%), and ileum (55%)
    • Digestion: breaks down double sugars into simple sugars, completes protein digestion, and aids in fat digestion
    • Absorption: water is absorbed along the length of the small intestine

    Large Intestine

    • Absorbs water and eliminates indigestible food from the body as feces
    • Does not participate in digestion of food
    • Structures: ileocecal valve, cecum, appendix, colon (ascending, transverse, descending, and sigmoidal), rectum, and anus
    • Functions: absorption of water, elimination of indigestible food, and production of vitamin K and B
    • Propulsion: slow, powerful movements (mass movements) occur three to four times per day

    Accessory Digestive Organs

    • Salivary glands: produce saliva that aids in chemical digestion

    • Pancreas: produces a wide spectrum of digestive enzymes that break down all categories of food

    • Liver: produces bile, detoxifies drugs and alcohol, degrades hormones, produces cholesterol, and plays a central role in metabolism### Anatomy of the Liver

    • The liver consists of four lobes suspended from the diaphragm and abdominal wall by the falciform ligament.

    • It is connected to the gallbladder via the common hepatic duct.

    Carbohydrate Metabolism

    • If the body has an abundance of glucose, it is converted into glycogen (glycogenesis).
    • If the body lacks sugar, the liver breaks down glycogen into sugar (glycogenolysis).
    • Glucose is broken down, releasing chemical energy to form ATP during cellular respiration.

    Fat Metabolism

    • Most fatty acid metabolism occurs in the liver.
    • Fats are broken down into acetic acid, and then oxidized to form CO2, H2O, and ATP.

    Protein Metabolism

    • Amino acids are used to make ATP only when proteins are excessive or carbohydrates and fats are unavailable.
    • Amino acids are oxidized, and ammonia (NH3) is secreted; the rest enter the citric acid cycle.

    Nutrition

    • A nutrient is a substance used by the body for growth, maintenance, and repair.
    • Categories of nutrients:
      • Carbohydrates (simple sugars, starches, fiber)
      • Lipids (triglycerides, phospholipids, fatty acids)
      • Proteins (amino acids)
      • Vitamins
      • Minerals (7 essential minerals: Ca, P, K, S, Na, Cl, Mg)
      • Water

    Diseases and Disorders

    • Gallstones occur when bile is stored for too long, and fat crystallizes.
    • Jaundice occurs when bile enters the bloodstream, and tissues become yellow.

    Processes of the Digestive System

    • Ingestion: getting food into the mouth
    • Food breakdown: mechanical and chemical digestion
    • Food movement: peristalsis and segmentation
    • Absorption: end products of digestion are absorbed into the blood or lymph
    • Defecation: elimination of indigestible substances

    Energy and Metabolism

    • Energy intake = total energy output (heat + work + storage energy)
    • Basal metabolic rate (BMR) is the amount of energy needed to perform essential life activities.
    • Factors that influence BMR: surface area, gender, age, and thyroid function.

    Urinary System

    • Functions:
      • Elimination of waste products
      • Maintenance of blood composition
    • Organs: kidneys, ureters, urinary bladder, and urethra

    Kidney Structure

    • Location: high on the posterior abdominal wall
    • Coverings: fibrous capsule, adipose capsule, and renal fascia
    • Regions: renal cortex, renal medulla, and renal pelvis

    Nephrons

    • Functional units of the kidneys
    • Consist of renal corpuscle and renal tubule
    • Responsible for forming urine
    • Over 1 million nephrons in each kidney

    Urine Formation

    • Processes: filtration, reabsorption, and secretion

    • Filtration: nonselective, passive process at the glomerulus

    • Regulation of filtration rate: sympathetic nervous system reflexes and hormonal regulation### Renal Function and Urine Production

    • Filtration pressure: hydrostatic pressure of blood forces substances through the capillary wall, while net filtration pressure is always positive.

    • Hydrostatic pressure of blood is greater than the hydrostatic pressure of the glomerulus capsule and the osmotic pressure of glomerulus plasma.

    • The sodium potassium pump reabsorbs 70% of sodium ions in the proximal convoluted tubule (PCT).

    The Renin-Angiotensin Mechanism

    • Renin is produced by juxtaglomerular cells in response to stimuli such as sympathetic stimulation, decreased blood pressure, and decreased sodium and chloride ions.
    • Renin reacts with angiotensinogen to form angiotensin I, which is converted to angiotensin II by the angiotensin I converting enzyme (ACE).
    • Angiotensin II acts to vasoconstrict efferent arterioles, increasing blood pressure and maintaining filtration rate.

    Reabsorption and Secretion

    • Reabsorption: water, glucose, amino acids, and needed ions are transported out of the filtrate into the peritubular capillary cells.
    • Most reabsorption occurs in the proximal convoluted tubule (PCT), where microvilli cells act as transporters.
    • Active transport of sodium ions occurs along the remainder of the nephron and collecting duct.
    • Almost all sodium ions and water are reabsorbed.
    • Secretion: hydrogen ions, potassium ions, creatinine, and drugs are removed from the peritubular capillaries and secreted into the filtrate.

    Maintaining Water Balance

    • Normal amount of water in the human body: 50% in young adult females, 60% in young adult males, 75% in babies, and 45% in older adults.
    • Water is necessary for many body functions, and levels must be maintained.
    • Distribution of body fluid: intracellular fluid (inside cells), extracellular fluid (outside cells), interstitial fluid, and blood plasma.
    • Electrolyte balance affects water movement between compartments.
    • Changes in electrolyte balance alter blood volume and blood pressure.
    • Aldosterone regulates sodium ion content of extracellular fluid.

    Urine Characteristics

    • Composition: ~95% water, containing urea, uric acid, electrolytes, and amino acids (trace amounts).
    • pH: 4.5 to 8.0, with acidic urine produced during protein-rich diet, starvation, and diabetes, and basic urine produced during bacterial infections and vegetarian diets.
    • Sterile, slightly aromatic, and yellow due to the pigment urochrome.

    Urinary System

    • Ureters: slender tubes attaching the kidney to the bladder, 10-12 inches long and ¼ inch diameter.
    • Urinary bladder: smooth, collapsible, muscular sac that temporarily stores urine.
    • Urethra: thin-walled tube that carries urine from the bladder to the outside of the body, with a length of 3-4 cm in females and 20 cm in males.

    Micturition (Voiding)

    • Both internal and external urethral sphincters must open to allow voiding.
    • The internal urethral sphincter is relaxed after the bladder stretches to ~200mL, and the external urethral sphincter must be voluntarily relaxed.
    • Incontinence: inability to control micturition, and retention: inability to micturate.

    Male Reproductive System

    • Testes: primary sex organs that produce sperm and secrete androgens such as testosterone.
    • Epididymis: comma-shaped, tightly coiled tube that matures and stores sperm cells.
    • Ductus deferens: carries sperm from the epididymis to the ejaculatory duct.
    • Urethra: carries both urine and sperm.
    • Accessory organs: seminal vesicle, prostate gland, and bulbourethral gland.
    • External genitalia: penis and scrotum.

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    Description

    This quiz covers the processes of the mouth, including mastication and digestion, and the breakdown of ingested food. Learn about the functions of the digestive system, including mechanical and chemical digestion.

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